While semiconductors and software continue to expand the capabilities of electronics products, a new kind of passive component is breaking into the fast lane. The memristor (short for memory varistor, or memory resistor) has been called the fourth type of passive component, with memristive characteristics distinctly different from the familiar resistance, capacitance, and inductance. Memristors were first formalized in 1971, followed by announcement of some of the first commercial-intent devices in 2008, and more recent developments which we reveal here. It seems clear that you will be hearing more about the memristor.